Do women earn less than men for the same exact work? [duplicate]

Question

Previous questions on the site such as this one and this one, as well as the answers and their sources address the gender pay gap on a broad scale, comparing the careers of all men to the careers of all women. The first one assumes a gender pay gap does exist, regardless of whether it is an aggregate phenomenon, and the second one is likewise asking about broader trends. However, I've often heard these statistics cited as evidence that women are paid less than men for the exact same work (same resume and position etc). Is there any evidence to suggest that this is true or false?

Answer 1

We don't know

From PolitiFact:

Just before Obama took office in 2009, the Department of Labor released a study because, as a deputy assistant secretary explained it, "The raw wage gap continues to be used in misleading ways to advance public policy agendas without fully explaining the reasons behind the gap." The study by CONSAD Research Corp. took into account women being more likely to work part-time for lower pay, leave the labor force for children or elder care, and choose work that is "family friendly" with fuller benefit packages over higher pay. The study found that, when factoring in those variables, the gap narrows to between 93 cents and 95 cents on the dollar.

and

Still, a study by the American Association of University Women controlled for a number of factors, including college major, occupation, age, geographical region and hours worked, and found a persistent 7 percent wage gap between men and women a year after graduating college.

So there remains a small gap after controlling for these factors. But there are other factors that differ between men and women. E.g., men commute longer distances. PDF source.

Women, particularly women with children, tend to have shorter commuting times than men which limits the range of jobs available to them. This potentially leads to the crowding of women into those jobs available locally, and in either case, depresses wages.

But neither of the studies controlled for that.

It's also worth noting that the first two studies didn't control for the same set of variables. This means that a new study could be done combining both and adding commute times. What would that study say? We don't know.

One reason why they don't do such studies is that the more variables you use, the less reliable regression analysis is.

• More likely for multicollinearity to occur.
• Some problems with the use of regression analysis in... PDF.

Another issue is that as you add more variables, the precision goes down. This is because you have to allow for the case that the error is positive or negative for all variables at once. So we tend to avoid regressions with large numbers of variables. But that doesn't mean that things aren't controlled by large numbers of correlated variables.

So we don't know the answer and are unlikely to get it. It is not possible to control for all possible variables accurately. And if we limit the variables, then it is always possible that the missing variables would fix it.

Answer 2

Depends on the study, and how you define "same work".

• Among women in USA, there's an unexplained pay gap of ~6%, as per Association of University Women (AAUW) study "Graduating to a Pay Gap"

  The AAUW researchers looked at male and female college graduates one year after graduation. After controlling for several relevant factors (though some were left out, as we shall see), they found that the wage gap narrowed to only 6.6 cents.

• However, for some demographics - at least in UK - if you explicitly restrict yourself to demographics less likely to be affected by parenting impacts, the gap either disappears or even reverses:

  The latest report from the Office of National Statistics is even more conclusive: the gender pay gap effectively doesn’t exist between the ages of 18 and 39. Between the ages of 22 and 29, women marginally out earn men. (source)